body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh; /* 设置父元素高度，以便让子元素垂直居中 */
}

div {
    width: 200px;
    height: 200px;
    line-height: 200px;
    text-align: center;
    background-color: #ccc;
    align-items: center;
}

a {
    padding: 10px;
    margin: 10px;
    background-color: #007bff;
    color: #fff;
    text-decoration: none;
    border-radius: 5px;
    font-size: 18px;
    font-weight: bold;
    text-transform: uppercase;
    transition: all 0.3s ease;
}

a:hover {
    background-color: #0056b3;
}